Fix another place that was assuming that a local variable declared as

"struct varlena" would be at least word-aligned.  Per buildfarm results
from gypsy_moth.  I did a little bit of trawling for other instances of
this coding pattern, and didn't find any; but if we turn up any more
of them I think we'd better revert the "char [4]" patch and find another
way of making tuptoaster.c alignment-safe.

src/backend/storage/large_object/inv_api.c

@@ -24,7 +24,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/storage/large_object/inv_api.c,v 1.127 2008/01/01 19:45:52 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/storage/large_object/inv_api.c,v 1.128 2008/03/01 19:26:22 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -516,7 +516,8 @@ inv_write(LargeObjectDesc *obj_desc, const char *buf, int nbytes)
 	struct
 	{
 		bytea		hdr;
-		char		data[LOBLKSIZE];
+		char		data[LOBLKSIZE];	/* make struct big enough */
+		int32		align_it;	/* ensure struct is aligned well enough */
 	}			workbuf;
 	char	   *workb = VARDATA(&workbuf.hdr);
 	HeapTuple	newtup;
@@ -707,7 +708,8 @@ inv_truncate(LargeObjectDesc *obj_desc, int len)
 	struct
 	{
 		bytea		hdr;
-		char		data[LOBLKSIZE];
+		char		data[LOBLKSIZE];	/* make struct big enough */
+		int32		align_it;	/* ensure struct is aligned well enough */
 	}			workbuf;
 	char	   *workb = VARDATA(&workbuf.hdr);
 	HeapTuple	newtup;